“If there’s a sign up and it says the road is closed, it means the road is closed,” he said. “We don’t close them for the fun of it.”

Three hours later, a 75-year-old man was swept to his death when his vehicle was inundated by fast-moving waters at Burpengary.

Queensland premier Annastacia Palaszczuk described the deaths as tragic, saying police investigations were under way. “On behalf of all Queenslanders we express our deepest sympathies,” she told reporters on Friday night.

She described the storm cell as “off the scale”.

Caboolture alone received 333mm of rain from 9am, with 277mm falling within three hours in the afternoon. The average rainfall for Brisbane for the month of May is 74mm but, as ABC weather presenter Jenny Woodward tweeted, the city has received a record amount of 181mm, with the previous mark having been 149mm in 1980. The Bureau of Meteorology has also said that some areas of Queensland experienced winds in excess of 100km/h.

At one point, the road to Caboolture hospital was cut off and new patients diverted to nearby hospitals.

The state emergency service had responded to 1,400 incidents throughout the day, and there were 19 swift-water rescues, Palaszczuk said.

The wild weather, caused by a low-pressure system, moved south to coincide with peak-hour traffic in the capital. Alistair Dawson, an assistant police commissioner of the Queensland police service offered advice to drivers. “Slow down, remember there are a lot of people trying to get home to their loved ones, and not to drive through flooded roads,” he said. “If it’s flooded, forget it. It’s better to arrive late than not at all.”

Dozens of people were rescued from flood waters, train services were suspended, flights delayed and cars were seen floating down roads that turned to rivers.

Dams including Wivenhoe, Somerset and North Pine were forced to release water and the NRL had to postpone the Anzac rugby league Test at Suncorp Stadium to Sunday.

The Suncorp Stadium. The Anzac Test between the Australia Kangaroos and the New Zealand Kiwis has been postponed. Photograph: Chris Hyde/Getty Images

“This has been an extreme weather event,” Palaszczuk said.

Conditions were expected to ease after the storm passed further south through the Gold Coast and hinterland, she added. But she urged Queenslanders to remain vigilant, obey road closures and keep away from creeks and waterways.

The low was expected to hit northern New South Wales in the early hours of Saturday morning with authorities preparing for the worst of the rain and winds over the next six to 12 hours, according the Bureau of Meteorology. 150 to 200mm of rain is expected in the region during that time with the possibility of 350mm in some areas.